Skip to main content

Clinician

Blog articles for clinicians and other medical professionals.

Overview of Pulmonary Contusion

March 26th, 2025

What is a Pulmonary Contusion?

Unlike pulmonary lacerations, contusions do not involve disruption of lung architecture but can significantly impair gas exchange and respiratory function.

Pulmonary contusion is the most frequent lung injury in blunt thoracic trauma, occurring in 30% to 75% of patients with severe chest trauma. It can occur in isolation or in conjunction with other injuries, such as rib fractures, pneumothorax, hemothorax, and flail chest.

The clinical impact of pulmonary contusion varies, with some cases resolving spontaneously, while others advance to respiratory failure and acute respiratory distress syndrome (ARDS). Given its significant morbidity and potential mortality, timely diagnosis and appropriate management are essential.

This article provides a detailed overview of pulmonary contusion, including its pathophysiology, clinical presentation, diagnostic approach, treatment strategies, potential complications, and prognostic factors.

Pathophysiology

Pulmonary contusion occurs due to direct or indirect trauma to the lung parenchyma. The mechanisms involved include:

  • Direct impact: A blunt force directly applied to the chest wall transmits kinetic energy to the underlying lung tissue, resulting in alveolar and capillary rupture.
  • Rapid deceleration: When a moving body abruptly stops (e.g., a motor vehicle collision), the lung tissue continues its motion due to inertia, leading to shearing forces between different lung regions.
  • Blast injuries: High-energy explosions produce pressure waves that damage the lung parenchyma without necessarily causing external thoracic injuries.

Physiological effects

The primary effects of pulmonary contusion include:

  • Alveolar hemorrhage: Disruption of alveolar capillaries leads to extravasation of blood into the alveolar spaces, impairing oxygen exchange.
  • Interstitial and alveolar edema: Increased vascular permeability and inflammation cause fluid accumulation in the lungs, further impairing gas exchange and compliance.
  • Ventilation-perfusion (V/Q) mismatch: The affected lung segments become poorly ventilated, leading to intrapulmonary shunting and hypoxemia.
  • Decreased lung compliance: Fluid accumulation and alveolar collapse increase the work of breathing, making ventilation more difficult.

Clinical presentation

The clinical manifestations of pulmonary contusion depend on the extent of lung injury. Symptoms may not be immediately apparent and often develop over several hours.

Common symptoms

  • Dyspnea and tachypnea: Respiratory distress can occur due to impaired gas exchange.
  • Chest pain: This is often exacerbated by deep breathing, coughing, or movement.
  • Cough and hemoptysis: Blood-tinged sputum can occur due to alveolar hemorrhage.
  • Cyanosis: This indicates severe hypoxemia.
  • Altered mental status: Hypoxia-related confusion or agitation, particularly in older patients, can be present.

Physical examination findings

  • Tachycardia and hypoxia: This is suggestive of impaired oxygenation.
  • Decreased breath sounds: Over-contused areas may occur due to alveolar collapse and edema.
  • Crackles (Rales): This is indicative of alveolar fluid accumulation.
  • Signs of associated injuries: Rib fractures, flail chest, pneumothorax, or hemothorax may be present.

Diagnostic approach

Imaging modalities

  • Chest radiography: This is an initial screening tool. Contusions appear as patchy, non-segmental opacities that are often missed in the first 24 hours.
  • Computed tomography (CT) scan: This is considered the gold standard for detecting pulmonary contusions. CT imaging can assess the severity, detect occult injuries, and guide management.
  • Ultrasound (Point-of-care): This can identify contusions as areas of comet tail artifacts, subpleural hypoechoic areas, and localized findings, although operator-dependent.

Laboratory tests

  • Lactate levels: This is useful for evaluating systemic perfusion in polytrauma patients.

Management strategies

Pulmonary contusion is managed primarily through supportive care. The severity of the contusion dictates the level of intervention required.

Oxygen therapy

  • Nasal cannula or face mask: This is for mild cases requiring oxygen supplementation.
  • High-flow nasal cannula (HFNC) or non-invasive ventilation (NIV): This is beneficial for patients with moderate hypoxemia and increased work of breathing.
  • Mechanical ventilation: This is used for severe cases with respiratory failure, following lung-protective strategies (low tidal volume, optimal PEEP).

Pain management

Adequate analgesia is crucial to prevent hypoventilation and subsequent atelectasis.

  • Non-opioid analgesics: Use NSAIDs or acetaminophen for mild pain.
  • Opioids (cautiously administered): Use for moderate to severe pain, but with close monitoring to avoid respiratory depression.
  • Regional techniques: Use epidural analgesia or intercostal nerve blocks for patients with rib fractures.

Fluid management

  • Avoid overhydration. Excess fluids can exacerbate pulmonary edema.
  • Use guided fluid resuscitation. Use hemodynamic monitoring to balance perfusion needs with pulmonary status.

Ventilatory support

Patients with worsening hypoxia or respiratory distress require escalation of ventilatory support:

  • Non-invasive positive pressure ventilation (NIPPV): Use in alert, cooperative patients with moderate respiratory compromise.
  • Invasive mechanical ventilation: This is indicated for patients with severe hypoxemia or ARDS.

Complications

  • Pneumonia: This occurs from impaired secretion clearance and atelectasis.
  • Pulmonary fibrosis: This happens in severe cases with prolonged inflammation.

Prognosis and outcomes

The prognosis of pulmonary contusion varies depending on severity, comorbidities, and associated injuries. Mild cases resolve within 7 to 10 days, whereas severe contusions can result in prolonged hospitalization, ventilator dependence, and increased mortality.

Predictors of poor outcome

  • Extent of contusion (>20% of lung volume on CT)
  • Hypoxia despite oxygen therapy
  • Presence of ARDS
  • Multisystem trauma or shock

Pulmonary contusion is a significant injury that may occur with blunt chest trauma, requiring prompt recognition and appropriate supportive management. Clinicians should remain vigilant for worsening respiratory function and secondary complications, including ARDS and pneumonia. Optimizing oxygenation, providing adequate analgesia, and preventing fluid overload are key principles in management.

While most cases resolve with conservative care, severe contusions may require intensive care intervention and prolonged respiratory support. Future research on targeted therapies to mitigate lung injury and inflammation may improve outcomes for patients with pulmonary contusion.